Anthropogenic impact accelerates antibiotic resistome diversity in the mangrove sediment of Indian Sundarban

Mangroves are situated in convergence zones between fresh and marine water and are prone to pollution and deforestation. This study explored the microbiome structure, function and antibiotic resistome of Indian Sun-darban. The taxonomic Chao1 estimated diversity was highest in uninhabited Kalash (1204.64 +/- 12.72) and lowest in Godkhali, which experiences considerable human activities (1158.76 +/- 11.18). The alpha diversity showed negative correlation (p < 0.05) with PAH such as Acenaphthene (r =-0.56), Acenaphthylene (r =-0.62), Fluoranthene (r =-0.59), Fluorene (r =-0.55), Phenanthrene (r =-0.57), while the biochemical parameters phosphate (r = 0.58) and salinity (r = 0.58) had a significant (p < 0.05) positive correlation. The data suggest the importance of physicochemical parameters in maintaining the mangrove microbiome. The taxonomic composition was dominated by Proteobacteria (54.12 +/- 0.37). All sites were dominated by ARGs such as rpoB2, cpxR, ompR, camP, and bacA. Comparing the Sundarban mangrove sediment resistome with mangrove from other sites in India (Kerala) and China (Guangxi, Hainan, and Shenzhen) suggested that resistome from Indian mangrove has a significantly (p < 0.05) higher ARG diversity compared to Chinese mangroves. Yet, the abundance of the ARG was significantly (p < 0.05) lower in the Indian mangroves posing a much greater risk if enriched. The study suggests that anthropogenic activities and pollution degrade the microbiome diversity, disturb the microbiome functions, and enrich ARGs.

Automated summary

Mangroves in India are vulnerable to pollution and deforestation. This study investigates the microbiome of the Sundarban mangrove and its antibiotic resistance genes. Physicochemical parameters play a crucial role in maintaining the mangrove microbiome. The Sundarban mangrove has a higher diversity of antibiotic resistance genes compared to Chinese mangroves, but lower abundance. Anthropogenic activities and pollution can degrade microbiome diversity, disrupt function, and enrich resistance genes.